Railway-traffic-controlling apparatus



Dec. 13, 1927.

s. M. LUCAS RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Aug. 12. 1926 E vN @BN fi S b K p\ -m Q EE g -u-@-@% Q\ @N W MN w v- AUI x dd Allll NW. N v

INVENTOR".

4 zwm/ Patented Dec. 13," 1927.

UNITED AT ATENT" OFFICE.

smnnn M. LUCAS, or PI TSBURGH, PENNSYLVANI ASSIGNOR r THE UNION swr'rcn & SIGNALCOMLEANY, or swIss-vALn, PENNSYLVANIA, A CORPORATION 0]! PENNSYLVANIA. A

RAILWAY-TRAFFIGCONTROLLING APPARATUS.

Application filed August 12, 1926; Serial No. 128,823.

My invention relates to railway trafiic controll ng apparatus, and particularly'to apparatns of the type. comprising train carried governing means controlled by energy retiilcliw ceived from, the trackway. More particumy present invention relates to the a, .portion of su'chapparatu's; In at iiaast one form of railway traffic controllingapparatus' of the type described, alternating. track circuit current is supplied to the track railsforthe control of trackway governing means, and alternating train controlling current is supplied to the rails for the control of train carried governing means. tion is the provision, in systems of this charactor, of means for preventing improper operation of. the trackway governing means by the train controllingcurrent. I a

I will describe oneform of trackway apparatus embodying my invention, and will thenpoint out the novel features thereof in claims-V 1 7 The accompanying drawing is a diagrammatic. view illustrating one form iof. track- -wa apparatus embodying myinvention.

cferring to this drawing,,the reference characters I and 1? designate the track rails of a stretch ofrailway track over which traffi'c normally moves'in the direction indicated by the arrow. 7 These rails are divided, by means of insulated joints 2;, into a pluralit of successive track sections, only one of W ich, A-B,, is shown in the'drawing.

The rails of section A B are supplied with alternatin track circuit current. from a transformer having its secondary 16 constantly connected across the rails adjiacent the entrance end of the section through the usual impedance 18. .The primary 17 of transformer D is constantly supplied with alternating current from a suitable source such asan alternator- N overl line wires 11 andvll.

V-L0cated adjacent the exit end of the section is a transformer'T comprising a nagnetizable core 3 carrying two windings t and 5, The right-hand e'ndjof winding i is connected with rail 1*, and. the right-hand end of windingfi'is connected with rail '1 adjacent the eXit' end of sectiouA-'B. The

One feature of my present inven-- free ends of windings t and5 are connected with a balancing network 9. The windings are so arranged that'the fluxes created n- ,core 3 by track circuit current flowing through. these windings and the network 9 from the rails of section AB are additive.

The core 3 is also provided with a third windingti, which is connected with winding 7 of a track relay R. The second winding 8 of the track relay is constantly'supplied with alternating current from line wires 11;

and 11 The fiux'created in core 3 due to track circuit current flowing in the track rails of section A'B' from transformer D therefore creates in winding 7 of track relay It a current of the same frequency as the ,trackcircuit currentand relay R is responsiveto such current to close its front contacts. Relay R is therefore energized by track circuit currentsupplied from transformer D when section A-B is unoccupied, and may be used to control governing means vnot shown in the drawing in any desired manner. I

Means are alsoprovided for supplying the rails of the section with alternating train controlling current. As here shown the immediate source of suchcurrent is a transformer 'Gr having a primary 13 constantly supplied with alternating current, from a separate source such as an alternator M,

ment is not essential. The secondary 12 of transformer G is connected with the midpoints 4 and 5 of windings at and 5, respectively, through a limiting resistance 15 and cordance with traflic conditions in advance.

As shown in the drawing each track section over line wires 10 and 10 but this arrangeis provided with a trackway signal desig A nated by the reference character '8 with a suitable exponent. Each'such signal is controlled by means forming no part of my present invention and omitted from the drawing for the sakelof simplicity, in such manner that the signal indicates proceed, caution or stop in accordance with. trailic conditions in advance. Associated with signal S a circuit controller K arranged to be closed only when signal S indicates proceed or caution. This circuit controller is inserted in circuit with secondary 12 of transformer G as here shown and it will therefore be seen that train controlling current is supplied to transformer T only when relay R is (lo-energized, and when signal S indicates caution or proceed. Under these conditions current flows from the right-hand terminal of secondary 12 of transformer G through wire 20, back contact 14 of relay R, wire 21, circuit controller K, wire 22. to the mid-point 4 of winding 4, thence through the right-hand half of winding 4 to rail 1 of section AB, and from rail 1 of this sec tion, through the right-hand half of winding 5, resistance 15 and wire- 23 back to sccondary 12 of transformer G. The circuit just traced is provided with a b anch which passes from wire 22, through the left-hand half of winding 4, balancingnetwork 9, and left-hand half of winding 5 to resistance 15. It will therefore be plain that train controlling current flows through the two halves of each of windings 4 and 5 in opposite directions. The balancing network 9 is a combination of resistors and reactors, and is so adjusted that its impedance is substantially equal to the impedance of the rails of section A-B in series at the frequency of the train controlling current. As a result, the fluxes created in core 3 bycurrents in the two branch paths just traced are opposite in direction and substantially equal in magnt tude. It follows that substantially no electromotive force is induced in winding 6, and no current is supplied torelay R, as a resultof train controlling current flowing in the windings of transformer T. i

In explaining the operation of the apparatus as a whole I will first assume that section A-B is unoccupied. Track circuit the section.

current supplied to the rails by transformer D therefore energizes relay B so that back contact 14 is open and secondary 12 of transformer G is disconnected from transformer T. Under these conditions no train controlling current is supplied to the rails of I will next assume that signal S .indicates caution or proceed and that a train enters section AB. The shunting effect of the wheels and axles of this train interrupts thesupply of track circuit current to transformer T so that relay R becomes de energized. thereby closing back contact it and supplying train controlling current to the rails of section A-B. But the operation of the transformer T and balancing network 9 prevents improper operation of the relay R by train controlling current.

The train controlling current supplied to the rails of the section maybe used to control train carried governing means of any suitable form. Train carried governing means responsive to alternating train controlling current in the trackway is usually controlled through the medium of a receiver carried on the train in advance of the forward axle With such apparatus it is essential with the train controlling current be supplied to the trackway from a point in advance of the train. One advantage of my invention is that train controlling current can be supplied to the exit end of a track section which isprovided with a'track relay also receiving track circuit current from the rails of the section adjacent the exit end thereof without any danger of improper operation of the relay by train controlling current.

Although I have herein shown and described only one form of railway traflic controlling apparatus embodying my invention it is understood that various changes and. modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what,

I laim is: a l

1. In combination with a stretch of railway track. a sourceof alternating track circuit current: connected with the rails of such section, a transformer having two windings connected in series with said rails, a source of alternating train controlling current connected with intermediate points on said two windings, a track relay, and a third winding on said transformer forsupplying said relay with track circuit current but not with train controlling current. i i i i 2. In combination with a stretch of railway track, a source of alternating track circuit currentconnected across the railsadjacent one end of said section, a transformer having two windings one terminal of each winding being connected with onerail adjacent the other end of the stretch. a source of alternating train controlling current connected with the mi d-pointsof said windings, a balancing network having substantially the same impedance at the frequency of said train controlling current as the rails of the stretch in series and connected across the free.

cent the other end of the stretch. a balanc inc network connected across the free terminals of said windings a track relay, :1 third winding on said transformer connected with said track relay, :1 source of alternating train controlling current, and means for connecting such last-mentioned source with the midpoints of said two windings respectively when said track relay is de energized.

4. In combination, with a stretch of railway track, asource of alternating track circuit current connected across the rails adjacent oneend of the section, a track relay, a I

source of alternating train controlling current, and means including a transformer and a balancing network for at times supplying the rails adjacent the other end of said stretch with current from the last-mentioned 15 source, such means permitting the supply of track circuit current to said relay from the rails of the stretch but preventing the supply of trains controlling current to such relay.

' In testimony whereof I aflix my signature.

SAMUEL M. LUCAS. 

